The present invention relates generally to automotive vehicle convertible roofs and more particularly to a convertible vehicle top stack mechanism having an active rearmost roof bow.
Some traditional convertible roofs for automotive vehicles employ an active number five bow which can be selectively rotated from a nominal and generally horizontal position to a raised and generally vertical position in order to allow clearance for a moveable, rigid tonneau cover. Such a tonneau cover needs to be opened to allow convertible roof access for retraction into a storage compartment or boot well, and the tonneau cover is closed so the number five roof bow can sit on top of it when the convertible roof is fully raised. One such example is disclosed in U.S. Pat. No. 6,039,382 entitled “Folding Top for a Motor Vehicle” which issued to Mather et al., on Mar. 21, 2000, and is incorporated by reference herein. Hydraulically driven buggy links have been used to move active number five roof bows in various of these conventional roof systems. Some exemplary U.S. patents disclosing these conventional constructions are: U.S. Pat. No. 5,816,644 entitled “Folding Top for a Convertible” which issued to Rothe et al. on Oct. 6, 1998; and U.S. Pat. No. 5,749,619 entitled “Motor Vehicle with Foldable Roof, and Foldable Roof for Such a Motor Vehicle” which issued to Mentink on May 12, 1998; both of these are incorporated by reference herein. It is noteworthy, however, that many traditional number five bow actuation systems have required undesirably high forces to operate which necessitates difficult to package, large and expensive hydraulic cylinders while increasing the chance of premature part failure. Furthermore, many of these traditional systems disadvantageously create undesirably fast acceleration of the number five bow during movement which can lead to premature part failure. Moreover, many of these traditional systems also disadvantageously push the backlite or rear window into the rear passenger area of the vehicle thereby limiting the usable passenger space during the raising and retracting of the convertible roof.
In accordance with the present invention, a vehicle convertible roof includes a rearmost roof member, a side roof rail, an actuator, and a link having a length that varies as the rearmost roof member is moved between a nominal and raised position. In another aspect of the present invention, a convertible vehicle top stack mechanism includes a number five roof bow, an actuator and an adjustable length link that varies in length as the number five roof bow moves between a nominal and raised position. In still another aspect of the present invention, a method of operating a convertible roof includes changing a length of a link coupled to the rearmost roof member during movement from a nominal position to a raised position and maintaining the link at a fixed length during movement of a roof rail from a raised position to a retracted position.
The convertible vehicle top stack mechanism of the present invention is advantageous over traditional constructions in that the present invention reduces the activation forces required to move a rearmost roof bow relative to a side rail while also reducing acceleration spikes during movement of the rearmost roof bow. The present invention is further advantageous by providing movement of the convertible roof that limits the intrusion of the backlite into the passenger space during the retraction and raising operation thereby reducing the operating envelope of the convertible roof. Accordingly, the present invention reduces part failure during usage, is easier to control, and requires a smaller operating space. Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.